I am developing small game on android, some kind of 3d mahjong. Currently it has two Activities:1) MainActivity - starting activity with list of available maps.2) FieldActivity - playground activity with GlSurfaceView where all show begins.When FieldActivity starts first all goes great. But when I close it and then open it again (by selecting other map) in log appears exception(on each call World.renderScene()) and display goes black:

jPCT seems to feel the need to send the mesh data to the gpu (again?) which somehow fails. I'm not sure what exactly "close and open it again" involves, so i'm not sure in which state the activity is after "opening it again" and which methods have been called and which don't. Can you post the log output prior to this exception please? Which version of jPCT-AE is that?

On first start of FieldActivity sample object is loaded from file and saved in static field. But on second start sample is already unusable and causes such exception. I really don't now why.So what is a proper way to do such things?

"close and open it again" means that I press BACK button when on FieldActivity and MainActivity becomes visible( instance of FiledActivity still can be in Activity steck), and then I send just the same intent to start FieldActivity like in first start:

Looks like as if you are stripping that static instance indirectly by calling strip() on the clones. Try to comment that out. Anyway, i'm not sure why you recreate your objects anyway. Have a look at the updated version of HelloWorld for Android in the wiki to get an idea how i'm doing this (not saying that that's the best way of doing it...).